Respiratory impairment and COPD hospitalisation in older persons: a competing risk analysis

Chronic obstructive pulmonary disease burden, grades and erythrocytosis at a tertiary hospital in western Uganda

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide among people over 40 years of age, and erythrocytosis is one of the major complications associated with increased mortality among COPD patients. The study aimed to determine the proportion of COPD, associated factors, and the burden of erythrocytosis among COPD participants.

METHODS AND MATERIALS

A descriptive cross-sectional study design was used. A consecutive sampling technique was used to obtain study participants at the Fort Portal Regional Referral Hospital outpatient clinic. Focused history and physical examination were carried out to select eligible participants. Participants were screened using the COPD population screener for spirometry after consenting to participate. The study enrolled all adults at risk of having COPD based on the COPD population screener and able to undergo spirometry. Spirometry was carried out according to the Global Chronic Obstructive Lung Disease and European Respiratory Society guidelines, and haemoglobin concentration was measured.

RESULTS

One hundred eighty participants were enrolled in the study, most of whom were females. The modal and mean age of participants was 60 years with 139 (77.2%) females and primary as the highest education level 149(82.8%). The proportion of COPD was 25% (45) [95% CI 18.9 - 32] and highest among females (68.9%) and those aged 60 years and above (70%). The combined COPD assessment tool groups had a proportion of 55.6%, 37.8%, 4.4%, and 2.2% for groups A, B, C, and D, respectively. Age < 50 years was protective against COPD, while for every additional year of smoking, there was an associated 6.5% increased risk compared to the general population. Additionally, the proportion of erythrocytosis among COPD participants was 6.7%.

CONCLUSIONS AND RECOMMENDATIONS

There was a high proportion of COPD among study participants (25%), with a 6.7% proportion of erythrocytosis. We recommend a complete blood count for every patient in groups C and D of the ABCD COPD GOLD groups.

Diffusing capacity in normal-for-age spirometry and spirometric impairments, using reference equations from the global lung function initiative

BACKGROUND

Reference equations from the Global Lung Function Initiative (GLI) are now available for both spirometry and diffusion. However, respiratory phenotypes defined by GLI-based measures of diffusion have not yet been evaluated in GLI-based normal-for-age spirometry or spirometric impairments.

METHODS

We evaluated cross-sectional data from 2100 Caucasians, aged 40-85 years. GLI-based spirometric categories included normal-for-age and the impairments of restrictive-pattern and three-level severity of airflow-obstruction (mild, moderate, severe). GLI-based diffusion included diffusing capacity of the lung for carbon monoxide (D_LCO) and measured components of alveolar volume (V_A) and transfer coefficient (K_CO): D_LCO = [V_A]x[K_CO]. Using multivariable regression models, adjusted odds ratios (adjORs) for D_LCO, V_A, and K_CO < lower limit of normal (LLN) were calculated for spirometric impairments, relative to normal-for-age spirometry.

RESULTS

Relative to normal-for-age spirometry, the restrictive-pattern increased the adjORs (95% confidence intervals) for D_LCO and V_A < LLN-4.61 (3.62, 5.85) and 15.53 (11.8, 20.4), respectively, but not for K_CO < LLN-1.02 (0.79, 1.33). Also relative to normal-for-age spirometry, airflow-obstruction from mild to severe increased the adjORs for D_LCO < LLN-from 1.22 (0.80, 1.86) to 6.63 (4.91, 8.95), for V_A < LLN-from 1.37 (0.85, 2.18) to 7.01 (5.20, 9.43), and for K_CO < LLN-from 2.04 (1.33, 3.14) to 3.03 (2.29, 3.99). Notably, in normal-for-age spirometry, 34.5%, 19.7%, and 25.3% of participants had D_LCO, V_A, or K_CO < LLN, respectively.

CONCLUSION

Abnormal diffusion is most prevalent in spirometric impairments but also occurs in normal-for-age spirometry. These results further inform the respiratory phenotypes of GLI-based spirometric categories and, in turn, the spirometric evaluation of respiratory disease.

Re-evaluation of the Uplift Clinical Trial Using Age-Appropriate Spirometric Criteria

BACKGROUND

The clinical trial of tiotropium in COPD, UPLIFT, enrolled adults with a mean age of 65 years and moderate-to-severe airflow obstruction, based on criteria from the Global Initiative for Chronic Obstructive Lung Disease (GOLD). For the UPLIFT cohort, however, GOLD-based criteria are not age-appropriate.

RESEARCH QUESTION

Will the use of more age-appropriate criteria for airflow obstruction from the Global Lung Function Initiative (GLI) modify the spirometric classification of the UPLIFT cohort and, in turn, the mortality effect of tiotropium in COPD?

STUDY DESIGN AND METHODS

Baseline spirometric classifications were first cross-tabulated by GLI- and GOLD-based criteria. Next, in GLI- and GOLD-based airflow obstruction, modified intention-to-treat analyses evaluated differences in time to death over 4 years, comparing tiotropium vs placebo. Because treatment response may differ by COPD severity, the mortality effect also was evaluated within stratum defined by GLI- and GOLD-based moderate and severe airflow obstruction.

RESULTS

Of 5,898 participants with GOLD-based airflow-obstruction, staged as moderate in 2,739 (46.4%) and severe in 3,156 (53.5%), GLI-based criteria established airflow obstruction in 5,750 (97.5%), staged as moderate in 795 (13.5%) and severe in 4,947 (83.9%). Relative to placebo, tiotropium yielded statistically nonsignificant adjusted hazard ratios (adjHRs) (95% CI) for death of 0.91 (0.80-1.04) and 0.91 (0.79-1.03) in GLI- and GOLD-based airflow obstruction, respectively. However, statistically significant effect modification was observed, but only in GLI-based moderate and severe airflow-obstruction, with tiotropium yielding adjHRs for death of 0.53 (0.34-0.81) and 0.99 (0.86-1.13), respectively. The P value for interaction was .007.

INTERPRETATION

Mortality reduction by tiotropium was only statistically significant in GLI-based moderate airflow-obstruction, a group that was underrepresented in UPLIFT because of severity misclassification by the original GOLD-based enrollment criteria.

Enhanced risk of traumatic brain injury in patients with chronic obstructive pulmonary disease

This study tests our hypothesis that patients with chronic obstructive pulmonary disease (COPD) have an increased risk of traumatic brain injury (TBI).

In this nationwide retrospective cohort study, we used a subset of Taiwan’s National Health Insurance Research Database, involving 1 million randomly selected beneficiaries. Patients with newly diagnosed COPD between 2000 and 2008 were identified. They were subgrouped as ‘COPD_AE+’ (if they had severe acute exacerbation of COPD during the follow-ups) or ‘COPD_AE−’ (if they had no acute exacerbation), and were frequency matched with randomly selected subjects without COPD (the ‘non-COPD’ group). Baseline differences were balanced by the inverse probability of treatment weighting based on the propensity score. For each patient, the risk of TBI during the subsequent 5 years was determined. The competing risk of death was controlled.

We identified 3734 patients in ‘COPD_AE+’, and frequency matched them with 11,202 patients in ‘COPD_AE−’ and 11,202 subjects in ‘non-COPD’. Compared with those in ‘non-COPD’, patients in ‘COPD_AE+’ and ‘COPD_AE−’ had an increased risk of TBI: the adjusted HR for ‘COPD_AE+’ was 1.50, 95% CI 1.31 to 1.73, and that for ‘COPD_AE−’ was 1.21, 95% CI 1.09 to 1.34. The highest risk was observed in the ‘COPD_AE+’ group that aged <65 (the adjusted HR was 1.92; 95% CI 1.39 to 2.64).

COPD has been linked to complications beyond the respiratory system. In this study we showed that COPD is associated with an increased risk of TBI.

FEV1 as a Standalone Spirometric Predictor and the Attributable Fraction for Death in Older Persons

BACKGROUND

Commonly used thresholds for staging FEV₁ have not been evaluated as standalone spirometric predictors of death in older persons. Specifically, the proportion of deaths attributed to a reduced FEV₁, when staged by commonly used thresholds in L, percent of predicted (% pred), and Z scores, has not been previously reported.

METHODS

In 4,232 white persons ≥ 65 y old, sampled from the Cardiovascular Health Study, FEV₁ was stratified as stage 1 (FEV₁ ≥ 2.00 L, ≥80% pred, and Z score ≥-1.64), stage 2 (FEV₁ 1.50-1.99 L, 50-79%pred, and Z score -2.55 to -1.63), and stage 3 (FEV₁ < 1.50 L, < 50% pred, and Z score < -2.55). Notably, a Z score threshold of -1.64 defines normal-for-age lung function as the lower limit of normal (ie, 5th percentile of distribution), and accounts for differences in age, sex, height, and ethnicity. Next, adjusted odds ratios and average attributable fractions for 10-y all-cause mortality were calculated, comparing FEV₁ stages 2 and 3 against stage 1, expressed in L, % pred, and Z scores. The average attributable fraction estimates the proportion of deaths attributed to a predictor by combining the prevalence of the predictor with the relative risk of death conferred by that predictor.

RESULTS

FEV₁ stage 2 and 3 in L, % pred, and Z scores yielded similar adjusted odds ratios of death: 1.40-1.51 for stage 2 and 2.35-2.66 for stage 3. Conversely, FEV₁ stages 2 and 3 in L, % pred, and Z scores differed in prevalence: 12.8-28.6% for stage 2 and 6.4-17.5% for stage 3, and also differed in the adjusted average attributable fraction for death: 3.2-6.4% for stage 2 and 4.5-9.1% for stage 3.

CONCLUSIONS

In older persons, the proportion of deaths attributed to a reduced FEV₁ is best stratified by Z score staging thresholds because these yield a similar relative risk of death but a more age- and sex-appropriate prevalence of FEV₁ stage.

Substantial variation exists in spirometry interpretation practices for airflow obstruction in accredited lung function laboratories across Australia and New Zealand

BACKGROUND

Spirometry forms the foundation investigation for the diagnosis and monitoring of common pulmonary conditions. However, potential variation in spirometry interpretation for airflow obstruction may impact subsequent clinical management.

AIM

To audit spirometry interpretation practices for airflow obstruction in Thoracic Society of Australia and New Zealand accredited laboratories.

METHODS

Thirty-nine accredited complex lung function laboratories were invited to participate in an online survey. The survey enquired about demographics, definition of lower limit of normal range for spirometry parameters, spirometric parameters used for identifying airflow obstruction, spirometric definition of airflow obstruction, definition of significant bronchodilator response and chosen spirometry reference equations.

RESULTS

Thirty-six laboratories provided complete responses (response rate, 92%). To define the lower limit of normal, 26 of 36 used the 5th percentile, 7 of 36 used a fixed cut-off and 3 used other. Twenty-nine laboratories utilised forced expiratory volume in 1 s/forced vital capacity (FEV₁ /FVC) as the sole parameter to identify airflow obstruction, 3 of 36 used FEV₁ /FVC and FEF_25-75% , and 4 used other. To define airflow obstruction, 25 of 36 laboratories used FEV₁ /FVC < 5th percentile, 9 of 36 used a fixed cut-off (FEV₁ /FVC < 0.7, 6/36; FEV₁ /FVC < 0.8, 2/36; FEV₁ /FVC < 0.75, 1/36) and 2 of 36 used other. Twenty-six laboratories defined a significant bronchodilator response as an increase of at least 200 mL and 12% in FEV₁ and/or FVC, 9 of 36 used ≥200 mL and ≥ 12% increase in FEV₁ only, and 1 used other criteria. Reference equations utilised for interpretation of spirometry data included: Quanjer 2012 Global Lung Initiative (16/36), the third National Health and Nutritional Examination Survey (8/36), European Community of Coal and Steel (8/36) and other (4/36).

CONCLUSIONS

Significant heterogeneity in spirometry interpretation for airflow obstruction exists across Australian and New Zealand accredited lung function laboratories. Lack of standardisation may translate into clinically appreciable differences for the diagnosis and management of common respiratory conditions. Ongoing discussion regarding formal standardisation is required.

Re-evaluation of combination therapy in chronic obstructive pulmonary disease (COPD)

BACKGROUND

Clinical trials of COPD pharmacotherapy typically involve aging populations with moderate-to-severe COPD, but the latter is often diagnosed by spirometric criteria that are not age-appropriate across the continuum of lung function. We have therefore re-evaluated the clinical effect of combination therapy (salmeterol plus fluticasone) in moderate-to-severe COPD, using more age-appropriate spirometric criteria from the Global Lung Function Initiative (GLI) and trial data from Towards a Revolution in COPD Health (TORCH).

METHODS

Of the 6112 TORCH participants, 5688 (93.1%) had GLI-based moderate-to-severe COPD (mean age 64.8 years). The primary outcome was all-cause mortality and the primary comparison was combination therapy vs. placebo. Secondary outcomes included COPD and cardiovascular (CV) mortality and pneumonia. A modified intention-to-treat analysis evaluated differences in time-to-event over a three-year period, using Cox proportional hazards models with statistical significance at p < 0.010 (acknowledging repeated significance testing).

RESULTS

Relative to placebo, combination therapy yielded a statistically non-significant reduction in all-cause mortality-adjusted hazard ratio [adjHR] 0.78 (95% confidence interval [CI]: 0.64, 0.95), p = 0.012. Relative to placebo, combination therapy also yielded statistically non-significant reductions in COPD and CV mortality-adjHR 0.75 (95% CI: 0.55, 1.02), p = 0.068 and adjHR 0.76 (95% CI: 0.53, 1.09), p = 0.135, respectively. In contrast, combination therapy yielded a statistically significant increased risk of pneumonia, relative to placebo-adjHR 1.80 (95% CI: 1.46, 2.21), p < 0.001.

CONCLUSION

In GLI-based moderate-to-severe COPD, combination therapy yields a statistically significant increased risk of pneumonia but the reductions in mortality are not statistically significant, although could potentially be clinically meaningful.

The Effect of Defining Chronic Obstructive Pulmonary Disease by the Lower Limit of Normal of FEV1/FVC Ratio in Tiotropium Safety and Performance in Respimat Participants

RATIONALE

There is continuing debate about whether to define airflow obstruction by a post-bronchodilator ratio of forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) below 0.70, or by ratio values falling below the age-dependent lower limit of normal (LLN) derived from general population data.

OBJECTIVES

To determine whether using the LLN criterion affects the classification and outcomes of patients previously defined as having chronic obstructive pulmonary disease by the fixed FEV₁/FVC ratio.

METHODS

We applied the LLN definition to pooled data from the Tiotropium Safety and Performance in Respimat study that used the fixed FEV₁/FVC ratio for the clinical diagnosis of chronic obstructive pulmonary disease.

RESULTS

A total of 17,072 patients were analyzed; of these, 1,807 (10.6%) patients had a ratio greater than or equal to LLN. Patients with a ratio greater than or equal to LLN had similar risks of death from any cause and fatal major adverse cardiovascular (CV) event as those below LLN. Patients with a ratio below LLN had a significantly lower risk of major adverse CV events (hazard ratio = 0.69; 95% confidence interval [CI] = 0.55-0.86; P = 0.001), and had significantly greater risks of moderate to severe exacerbation (rate ratio = 1.48; 95% CI = 1.36-1.61; P < 0.0001) and severe exacerbation (rate ratio = 2.01; 95% CI = 1.68-2.40; P < 0.0001) when compared with patients greater than or equal to LLN. Study outcomes by treatment arm (5 μg tiotropium Respimat vs. 18 μg HandiHaler) were comparable.

CONCLUSIONS

Using the LLN to define airflow obstruction would have excluded patients in the Tiotropium Safety and Performance in Respimat study with a higher risk of nonfatal major adverse CV events and a lower risk of exacerbation; study outcomes by treatment arm (2.5 μg/5 μg tiotropium Respimat vs. 18 μg HandiHaler) remained similar. Clinical trial registered with www.clinicaltrials.gov (NCT01126437).

Classical regression equations of spirometric parameters are not applicable for diagnosing spirometric abnormalities in adipotic adults

The prevalence of overweighing and obese adults (defined as “adipotic” adults), has markedly increased over the world. A remarkable increase in the adipotic population urgently needs developing the regression equations for predicting spirometric parameters (SPs), which are specifically applicable to adipotic adults. Unfortunately, however, the reliable equations suitable for adipotic adults have not been reported to date. Recently, Yamaguchi et al have proposed the quantitative method to estimate the effects of adiposity on deciding the SPs incorporating with age-specific contributions of various explanatory, independent variables such as age (A), standing height (H), body weight (BW), and fat fraction of body mass (F). Extending the method proposed by Yamaguchi et al, we attempted to elaborate the novel regression equations applicable for diagnosing the spirometric abnormality in adipotic adults. For accomplishing this purpose, never-smoking, adipotic adults with body mass index (BMI) over 25 kg/m² and no respiratory illness were recruited from the general population in Japan (n = 3696, including men: 1890 and women: 1806). Introducing the four explanatory variables of A, H, BW, and F, gender-specific and age-dependent regression equations that allowed for prescribing the SPs in adipotic adults were constructed. Comparing the results obtained for non-adipotic adults (i.e., those with normal BMI), the negative or positive impact of height on SPs was preserved in adipotic adults, as well. However, the negative impact of age on SPs was blunted in adipotic men and the positive effect of BW on SPs was impeded in adipotic men and women. The fat fraction of body mass-elicited negative impact on SPs vanished in adipotic women. These results indicate that the regression equations of SPs for adipotic adults differ significantly from those for non-adipotic adults, leading to the conclusion that the regression equations for non-adipotic adults should not be used while judging the spirometric abnormalities in adipotic adults.

Inappropriate inhaled corticosteroid prescribing in chronic obstructive pulmonary disease patients

The Australian National Chronic Obstructive Pulmonary Disease (COPD) guidelines recommend that inhaled corticosteroids (ICS) be reserved for patients with a post-bronchodilator forced expiratory volume in 1 s (FEV₁ ) less than 50% predicted and those who experience ≥2 exacerbations in 12 months. In total, 707 COPD patients were identified from the lung function test database at our tertiary hospital; 52.4% of patients with a post-bronchodilator FEV₁ ≥50% were prescribed an ICS. Significant discordance exists between guideline recommendations and inhaler prescription.

Comparison of different staging methods for COPD in predicting outcomes

Chronic obstructive pulmonary disease (COPD) is commonly staged according to the percentage of predicted forced expiratory volume in 1 s (FEV₁ % pred), but other methods have been proposed. In this study we compared the performance of seven staging methods in predicting outcomes.We retrospectively studied 296 COPD outpatients. For each patient the disease severity was staged by separately applying the following methods: the criteria proposed by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), quartiles of FEV₁ % pred and z-score of FEV₁, quartiles and specified cut-off points of the ratio of FEV₁ over height squared ((FEV₁·Ht^-2)_A and (FEV₁·Ht^-2)_B, respectively), and quartiles of the ratio of FEV₁ over height cubed (FEV₁·Ht^-3) and of FEV₁ quotient (FEV₁Q). We evaluated the performance of these methods in predicting the risks of severe acute exacerbation and all-cause mortality.Overall, staging based on the reference-independent FEV₁Q performed best in predicting the risks of severe acute exacerbation (including frequent exacerbation) and mortality, followed by (FEV₁·Ht^-2)_B The performance of staging methods could also be influenced by the choice of cut-off values. Future work using large and ethnically diverse populations to refine and validate the cut-off values would enhance the prediction of outcomes.

Spirometric Criteria for Chronic Obstructive Pulmonary Disease in Clinical Trials of Pharmacotherapy

Clinical trials of pharmacotherapy in chronic obstructive pulmonary disease (COPD) often include older persons with moderate-to-severe airflow-obstruction, as defined by the Global Initiative for chronic Obstructive Lung Disease (GOLD). In this context, spirometric airflow-obstruction establishes COPD. Because GOLD misidentifies COPD and its severity in older persons, we set out to apply more age-appropriate spirometric criteria from the Global Lung function Initiative (GLI) in a prior clinical trial of COPD pharmacotherapy, specifically the Towards a Revolution in COPD Health (TORCH) trial - N = 6,112, mean age 65 years. In the TORCH trial, which enrolled GOLD-defined moderate COPD (26.2%, n = 1,200) and GOLD-defined severe COPD (73.8%, n = 4,511), the GLI reclassification yielded a higher frequency of severe COPD (89.6%, n = 5,474), the inclusion of restrictive-pattern (6.9%, n = 420) and, in turn, a very low frequency of moderate COPD (3.5%, n = 212). These GLI reclassification results suggest that GOLD-based enrollment criteria for the TORCH trial may have assembled a cohort that was: 1) less likely to respond to COPD pharmacotherapy, given the greater representation of severe COPD, very minor representation of moderate COPD, and inclusion of a non-obstructive spirometric impairment (restrictive-pattern); and 2) more likely to have medication-related adverse events, given the inappropriate use of COPD pharmacotherapy in misidentified COPD (restrictive-pattern). We therefore propose that future clinical trials of COPD pharmacotherapy should consider GLI criteria for defining COPD, including a greater representation of GLI-defined moderate COPD.

The subsequent course of disability in older persons discharged to a skilled nursing facility after an acute hospitalization

OBJECTIVES

To evaluate the association between the type of acute hospitalization and subsequent course of disability in older persons discharged to a skilled nursing facility (SNF).

DESIGN

Longitudinal study of 754 community-living persons aged 70 or older.

PARTICIPANTS

The analytical sample included 365 participants who had one or more admissions to a SNF after an acute hospitalization (n=520 index admissions).

MEASUREMENTS

Information on hospitalizations, SNF admissions, and disability was ascertained over 15years. The primary and secondary outcomes were disability burden and recovery of pre-hospital function, respectively, assessed monthly over a 6-month period. Index admissions were classified into four mutually exclusive groups based on the type of hospitalization: elective major surgery, non-elective major surgery, critical illness, and other.

RESULTS

Disability worsened considerably after hospitalization for each of the four groups. Relative to elective major surgery, the disability burden over 6months was significantly greater for non-elective major surgery, critical illness, and other hospitalizations, with adjusted rate ratios (RRs) of 1.37 (95% CI 1.19 to 1.59), 1.37 (95% CI 1.19 to 1.58), and 1.29 (95% CI 1.14 to 1.47), respectively. Overall, recovery to pre-hospital function was observed in only 132 (25.4%) admissions. Relative to elective major surgery, the likelihood of recovering pre-hospital function was considerably lower for each of the three other groups. The results were consistent for basic, instrumental and mobility activities.

CONCLUSION

Among older persons discharged to a SNF after an acute hospitalization, the functional course over 6months was generally poor, with recovery to pre-hospital function observed in only one out of every four cases. Relative to elective major surgery, functional outcomes were worse for non-elective major surgery, critical illness, and other hospitalizations.

Spirometry, Static Lung Volumes, and Diffusing Capacity

BACKGROUND

Spirometric Z-scores from the Global Lung Initiative (GLI) rigorously account for age-related changes in lung function and are thus age-appropriate when establishing spirometric impairments, including a restrictive pattern and air-flow obstruction. However, GLI-defined spirometric impairments have not yet been evaluated regarding associations with static lung volumes (total lung capacity [TLC], functional residual capacity [FRC], and residual volume [RV]) and gas exchange (diffusing capacity).

METHODS

We performed a retrospective review of pulmonary function tests in subjects ≥40 y old (mean age 64.6 y), including pre-bronchodilator measures for: spirometry (n = 2,586), static lung volumes by helium dilution with inspiratory capacity maneuver (n = 2,586), and hemoglobin-adjusted single-breath diffusing capacity (n = 2,508). Using multivariable linear regression, adjusted least-squares means (adj_LSMeans) were calculated for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity. The adj_LSMeans were expressed with and without height-cubed standardization and stratified by GLI-defined spirometry, including normal (n = 1,251), restrictive pattern (n = 663), and air-flow obstruction (mild, [n = 128]; moderate, [n = 150]; and severe, [n = 394]).

RESULTS

Relative to normal spirometry, restrictive-pattern had lower adj_LSMeans for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity (P ≤ .001). Conversely, relative to normal spirometry, mild, moderate, and severe air-flow obstruction had higher adj_LSMeans for FRC and RV (P < .001). However, only mild and moderate air-flow obstruction had higher adj_LSMeans for TLC (P < .001), while only moderate and severe air-flow obstruction had higher adj_LSMeans for RV/TLC (P < .001) and lower adj_LSMeans for hemoglobin-adjusted single-breath diffusing capacity (P < .001). Notably, TLC (calculated as FRC + inspiratory capacity) was not increased in severe air-flow obstruction (P ≥ .11) because inspiratory capacity decreased with increasing air-flow obstruction (P < .001), thus opposing the increased FRC (P < .001). Finally, P values were similar whether adj_LSMeans were height-cubed standardized.

CONCLUSIONS

A GLI-defined spirometric restrictive pattern is strongly associated with a restrictive ventilatory defect (decreased TLC, FRC, and RV), while GLI-defined spirometric air-flow obstruction is strongly associated with hyperinflation (increased FRC) and air trapping (increased RV and RV/TLC). Both spirometric impairments were strongly associated with impaired gas exchange (decreased hemoglobin-adjusted single-breath diffusing capacity).

Phenotype of Spirometric Impairment in an Aging Population

RATIONALE

The Global Lung Initiative (GLI) provides age-appropriate criteria for establishing spirometric impairment, including mild, moderate, and severe chronic obstructive pulmonary disease (COPD) and restrictive pattern, but its association with respiratory-related phenotypes has not been evaluated.

OBJECTIVES

To evaluate respiratory-related phenotypes in GLI-defined spirometric impairment.

METHODS

In COPDGene (N = 10,131 patients; age range, 45-81 yr; average smoking history, 44.3 pack-years), we evaluated spirometry, dyspnea (modified Medical Research Council grade, ≥2), poor respiratory health-related quality of life (St. George's Respiratory Questionnaire total score, ≥25), poor exercise performance (6-minute-walk distance, <391 m), bronchodilator reversibility (FEV1 change, >12% and ≥200 ml), and computed tomography-diagnosed emphysema and gas trapping (>5% and >15% of lung, respectively).

MEASUREMENTS AND MAIN RESULTS

GLI established normal spirometry in 5,100 patients (50.3%), mild COPD in 669 (6.6%), moderate COPD in 865 (8.5%), severe COPD in 2,522 (24.9%), and restrictive pattern in 975 (9.6%). Relative to normal spirometry, graded associations with respiratory-related phenotypes were found for mild, moderate, and severe COPD, with respective adjusted odds ratios (95% confidence intervals) as follows: dyspnea-1.31 (1.10-1.56), 2.20 (1.81-2.68), and 10.73 (8.04-14.33); poor respiratory health-related quality of life-1.49 (1.28-1.75), 2.69 (2.08-3.47), and 14.61 (10.09-21.17); poor exercise performance-1.11 (0.94-1.31), 1.58 (1.33-1.88), and 4.58 (3.42-6.12); bronchodilator reversibility-2.76 (2.24-3.40), 5.18 (4.29-6.27), and 6.21 (5.06-7.62); emphysema-4.86 (3.16-7.47), 6.41 (4.09-10.05), and 17.79 (10.79-29.32); and gas trapping-3.92 (3.12-4.93), 5.20 (3.82-7.07), and 16.28 (9.71-27.30). Restrictive pattern was also associated with multiple respiratory-related phenotypes at a level similar to moderate COPD, but it was otherwise not associated with emphysema (0.89 [0.60-1.32]) or gas trapping (1.15 [0.92-1.42]).

CONCLUSIONS

GLI-defined spirometric impairment establishes clinically meaningful respiratory disease, as validated by graded associations with respiratory-related phenotypes.

Effect of Structured Physical Activity on Respiratory Outcomes in Sedentary Elderly Adults with Mobility Limitations

OBJECTIVES

To evaluate the effect of structured physical activity on respiratory outcomes in community-dwelling elderly adults with mobility limitations.

DESIGN

Multicenter, randomized trial of physical activity vs health education, with respiratory variables prespecified as tertiary outcomes over an intervention period of 24-42 months. Physical activity included walking (goal of 150 min/week) and strength, flexibility, and balance training. Health education included workshops on topics relevant to older adults and upper extremity stretching exercises.

SETTING

Lifestyle Interventions and Independence in Elders (LIFE) Study.

PARTICIPANTS

Community-dwelling persons aged 70-89 with Short Physical Performance Battery scores less than 10 (N = 1,635).

MEASUREMENTS

Dyspnea severity (defined as moderate to severe according to a Borg index >2 immediately after a 400-m walk), forced expiratory volume in 1 second (FEV1) (<lower limit of normal (LLN) defined low breathing capacity), and maximal inspiratory pressure (MIP) (<LLN defined respiratory muscle weakness) were assessed at baseline and 6, 18, and 30 months. Hospitalization for exacerbation of obstructive airways disease (EOAD) and pneumonia was also ascertained over the 42-month follow-up period.

RESULTS

The randomized groups were similar in baseline demographics, including mean age (79) and sex (67% female). The effect of physical activity on dyspnea severity, FEV1, and MIP was no different from that of health education but was associated with higher likelihood of respiratory hospitalization, significantly for EOAD (hazard ratio (HR) = 2.34, 95% confidence interval (CI) = 1.19-4.61, P = .01) and marginally for pneumonia (HR = 1.54, 95% CI = 0.98-2.42, P = .06).

CONCLUSION

In older persons with mobility limitations, physical activity was associated with higher likelihood of respiratory hospitalization than health education, but differences in dyspnea severity, FEV1, and MIP did not accompany this effect-indicating that higher hospital use could be attributable to greater participant contact.

Individualized Absolute Risk Calculations for Persons with Multiple Chronic Conditions: Embracing Heterogeneity, Causality, and Competing Events

Approximately 75% of adults over the age of 65 years are affected by two or more chronic medical conditions. We provide a conceptual justification for individualized absolute risk calculators for competing patient-centered outcomes (PCO) (i.e. outcomes deemed important by patients) and patient reported outcomes (PRO) (i.e. outcomes patients report instead of physiologic test results). The absolute risk of an outcome is the probability that a person receiving a given treatment will experience that outcome within a pre-defined interval of time, during which they are simultaneously at risk for other competing outcomes. This allows for determination of the likelihood of a given outcome with and without a treatment. We posit that there are heterogeneity of treatment effects among patients with multiple chronic conditions (MCC) largely depends on those coexisting conditions. We outline the development of an individualized absolute risk calculator for competing outcomes using propensity score methods that strengthen causal inference for specific treatments. Innovations include the key concept that any given outcome may or may not concur with any other outcome and that these competing outcomes do not necessarily preclude other outcomes. Patient characteristics and MCC will be the primary explanatory factors used in estimating the heterogeneity of treatment effects on PCO and PRO. This innovative method may have wide-spread application for determining individualized absolute risk calculations for competing outcomes. Knowing the probabilities of outcomes in absolute terms may help the burgeoning population of patients with MCC who face complex treatment decisions.

Phenotype of normal spirometry in an aging population

RATIONALE

In aging populations, the commonly used Global Initiative for Chronic Obstructive Lung Disease (GOLD) may misclassify normal spirometry as respiratory impairment (airflow obstruction and restrictive pattern), including the presumption of respiratory disease (chronic obstructive pulmonary disease [COPD]).

OBJECTIVES

To evaluate the phenotype of normal spirometry as defined by a new approach from the Global Lung Initiative (GLI), overall and across GOLD spirometric categories.

METHODS

Using data from COPDGene (n = 10,131; ages 45-81; smoking history, ≥10 pack-years), we evaluated spirometry and multiple phenotypes, including dyspnea severity (Modified Medical Research Council grade 0-4), health-related quality of life (St. George's Respiratory Questionnaire total score), 6-minute-walk distance, bronchodilator reversibility (FEV1 % change), computed tomography-measured percentage of lung with emphysema (% emphysema) and gas trapping (% gas trapping), and small airway dimensions (square root of the wall area for a standardized airway with an internal perimeter of 10 mm).

MEASUREMENTS AND MAIN RESULTS

Among 5,100 participants with GLI-defined normal spirometry, GOLD identified respiratory impairment in 1,146 (22.5%), including a restrictive pattern in 464 (9.1%), mild COPD in 380 (7.5%), moderate COPD in 302 (5.9%), and severe COPD in none. Overall, the phenotype of GLI-defined normal spirometry included normal adjusted mean values for dyspnea grade (0.8), St. George's Respiratory Questionnaire (15.9), 6-minute-walk distance (1,424 ft [434 m]), bronchodilator reversibility (2.7%), % emphysema (0.9%), % gas trapping (10.7%), and square root of the wall area for a standardized airway with an internal perimeter of 10 mm (3.65 mm); corresponding 95% confidence intervals were similarly normal. These phenotypes remained normal for GLI-defined normal spirometry across GOLD spirometric categories.

CONCLUSIONS

GLI-defined normal spirometry, even when classified as respiratory impairment by GOLD, included adjusted mean values in the normal range for multiple phenotypes. These results suggest that among adults with GLI-defined normal spirometry, GOLD may misclassify normal phenotypes as having respiratory impairment.

Respiratory disability and impairment: what is new?

PURPOSE OF REVIEW

This review summarizes recent advances concerning respiratory impairment and disability.

RECENT FINDINGS

The traditional impairment assessment approach, depending heavily on clinical pulmonary function testing to estimate the match between the patient's sustainable oxygen consumption and the workplace requirements, continues to be widely used. Recent work indicates the need to reassess underlying concepts for several reasons: The relationship between basic pulmonary function tests and sustainable oxygen consumption varies among patients and conditions. Studies of the respiratory demands of modern workplaces need to be updated. The concepts are less easily applied to asthma than other disorders. Research studies present differing definitions of 'disability', and therefore the methods of relating impairment (function loss) and disability require reassessment. Recent advances provide improved understanding of the large societal and personal impacts of respiratory impairment and disability.

SUMMARY

Clinicians, policymakers, and researchers should carefully consider how well the current highly specified impairment rating systems can be improved for accuracy and relevance to current home and work activities. In addition to measuring 'impairment', clinicians should consider factors affecting how impairments lead to disability.

Epidemiology of Chronic Obstructive Pulmonary Disease (COPD) in Aging Populations

Current epidemiologic practice evaluates COPD based on self-reported symptoms of chronic bronchitis, self-reported physician-diagnosed COPD, spirometry confirmed airflow obstruction, or emphysema diagnosed by volumetric computed chest tomography (CT). Because the highest risk population for having COPD includes a predominance of middle-aged or older persons, aging related changes must also be considered, including: 1) increased multimorbidity, polypharmacy, and severe deconditioning, as these identify mechanisms that underlie respiratory symptoms and can impart a complex differential diagnosis; 2) increased airflow limitation, as this impacts the interpretation of spirometry confirmed airflow obstruction; and 3) "senile" emphysema, as this impacts the specificity of CT-diagnosed emphysema. Accordingly, in an era of rapidly aging populations worldwide, the use of epidemiologic criteria that do not rigorously consider aging related changes will result in increased misidentification of COPD and may, in turn, misinform public health policy and patient care.

Aging-Related Considerations When Evaluating the Forced Expiratory Volume in 1 Second (FEV1) Over Time

BACKGROUND

Forced expiratory volume in 1 second (FEV1) over time is commonly expressed in liters and percent predicted (%Pred), or alternatively in L/m(3) and Z-scores-which approach is more clinically meaningful has not been evaluated. Because it uniquely accounts for the effect of aging on FEV1 and spirometric performance, we hypothesized that the Z-score approach is more clinically meaningful, based on associations between cardiopulmonary predictors and FEV1 over time.

METHODS

Using linear mixed-effects models and data from the Baltimore Longitudinal Study on Aging, including 501 white participants aged 40-95 who had completed at least three longitudinal spirometric assessments, we evaluated the associations between cardiopulmonary predictors (obesity, smoking status, hypertension, chronic bronchitis, diabetes mellitus, and myocardial infarction) and FEV1 over time, in liters, %Pred, L/m(3), and Z-scores.

RESULTS

Mean baseline values for FEV1 were 3.240L, 96.4%Pred, 0.621L/m(3), and -0.239 as a Z-score (40.6th percentile). The annual decline in FEV1 was 0.040L, 0.234 %Pred, 0.007L/m(3), and 0.008 Z-score units. Baseline age was associated with FEV1 over time in liters and L/m(3) (p < .001), and included a time interaction for %Pred (p < .001), but was not associated with Z-scores (p = .933). The associations of cardiopulmonary predictors with FEV1 over time were all significant when using Z-scores (p < .05), but varied for other methods of expressing FEV1.

CONCLUSION

A Z-score approach is more clinically meaningful when evaluating FEV1 over time, as it accounted for the effect of aging and was more frequently associated with multiple cardiopulmonary predictors.

Respiratory symptoms, spirometric respiratory impairment, and respiratory disease in middle-aged and older persons

OBJECTIVES

To evaluate whether a novel definition of spirometric respiratory impairment from the Global Lung Initiative (GLI) is strongly associated with respiratory symptoms and, in turn, frequently establishes symptomatic respiratory disease.

DESIGN

Cross-sectional.

SETTING

Third National Health and Nutrition Examination Survey.

PARTICIPANTS

Community-dwelling individuals aged 40 to 80 (N = 7,115).

MEASUREMENTS

GLI-defined spirometric respiratory impairment (airflow obstruction and restrictive pattern), dyspnea on exertion (DOE), chronic bronchitis (CB), and wheezing.

RESULTS

Prevalence rates were 12.7% for airflow obstruction, 6.2% for restrictive pattern, 28.6% for DOE, 12.6% for CB, and 12.9% for wheezing. Airflow obstruction was associated with DOE (adjusted odds ratio (aOR) = 1.69, 95% confidence interval (CI) = 1.42-2.02), CB (aOR = 1.92, 95% CI = 1.62-2.29), and wheezing (aOR = 2.50, 95% CI = 2.08-3.00), and restrictive pattern was associated with DOE (aOR = 1.75, 95% CI = 1.36-2.25), CB (aOR = 1.39, 95% CI = 1.08-1.78), and wheezing (aOR = 1.53, 95% CI = 1.15-2.04). Nonetheless, among participants who had airflow obstruction and restrictive pattern, only a minority had DOE (38.6% and 45.5%), CB (23.3% and 15.9%), and wheezing (24.4% and 19.1%), yielding a positive predictive value (PPV) of only 53% for any respiratory symptom in the setting of any spirometric respiratory impairment. In addition, most participants who had DOE (73.0%), CB (67.8%), and wheezing (66.8%) did not have airflow obstruction or restrictive pattern, yielding a PPV of only 26% for any spirometric respiratory impairment in the setting of any respiratory symptom. The results differed only modestly when stratified according to age (40-64 vs 65-80).

CONCLUSION

GLI-defined spirometric respiratory impairment increased the likelihood of respiratory symptoms but was nonetheless a poor predictor of respiratory symptoms. Similarly, respiratory symptoms were poor predictors of GLI-defined spirometric respiratory impairment. Hence, a comprehensive assessment is needed when evaluating respiratory symptoms, even in the presence of spirometric respiratory impairment.

In-hospital and one-year mortality and their predictors in patients hospitalized for first-ever chronic obstructive pulmonary disease exacerbations: a nationwide population-based study

Introduction

Natural history of chronic obstructive pulmonary disease (COPD) is punctuated by exacerbations; however, little is known about prognosis of the first-ever COPD exacerbation and variables predicting its outcomes.

Materials and Methods

A population-based cohort study among COPD patients with their first-ever exacerbations requiring hospitalizations was conducted. Main outcomes were in-hospital mortality and one-year mortality after discharge. Demographics, comorbidities, medications and in-hospital events were obtained to explore outcome predictors.

Results

The cohort comprised 4204 hospitalized COPD patients, of whom 175 (4%) died during the hospitalization. In-hospital mortality was related to higher age (odds ratio [OR]: 1.05 per year; 95% confidence interval [CI]: 1.03–1.06) and Charlson comorbidity index score (OR: 1.08 per point; 95% CI: 1.01–1.15); angiotensin II receptor blockers (OR: 0.61; 95% CI: 0.38–0.98) and β blockers (OR: 0.63; 95% CI: 0.41–0.95) conferred a survival benefit. At one year after discharge, 22% (871/4029) of hospital survivors were dead. On multivariate Cox regression analysis, age and Charlson comorbidity index remained independent predictors of one-year mortality. Longer hospital stay (hazard ratio [HR] 1.01 per day; 95% CI: 1.01–1.01) and ICU admission (HR: 1.33; 95% CI: 1.03–1.73) during the hospitalization were associated with higher mortality risks. Prescription of β blockers (HR: 0.79; 95% CI: 0.67–0.93) and statins (HR: 0.66; 95% CI: 0.47–0.91) on hospital discharge were protective against one-year mortality.

Conclusions

Even the first-ever severe COPD exacerbation signifies poor prognosis in COPD patients. Comorbidities play a crucial role in determining outcomes and should be carefully assessed. Angiotensin II receptor blockers, β blockers and statins may, in theory, have dual cardiopulmonary protective properties and probably alter prognosis of COPD patients. Nevertheless, the limitations inherent to a claims database study, such as the diagnostic accuracy of COPD and its exacerbation, should be born in mind.

Respiratory impairment and dyspnea and their associations with physical inactivity and mobility in sedentary community-dwelling older persons

OBJECTIVES

To evaluate the prevalence of respiratory impairment and dyspnea and their associations with objectively measured physical inactivity and performance-based mobility in sedentary older persons.

DESIGN

Cross-sectional.

SETTING

Lifestyle Interventions and Independence for Elders Study.

PARTICIPANTS

Community-dwelling older persons (n = 1,635, mean age 78.9) who reported being sedentary (<20 min/wk of regular physical activity and <125 min/wk of moderate physical activity in past month).

MEASUREMENTS

Respiratory impairment was defined as low ventilatory capacity (forced expiratory volume in 1 second less than lower limit of normal (LLN)) and respiratory muscle weakness (maximal inspiratory pressure <LLN). Dyspnea was defined as moderate to severe ratings on the modified Borg index, immediately after a 400-m walk test (400-MWT). Physical inactivity was defined according to high sedentary time as the highest quartile of participants with accelerometry-measured activity of <100 counts/min. Performance-based mobility was evaluated using the Short Physical Performance Battery (≤ 7 defined as moderate to severe mobility impairment) and 400-MWT gait speed (<0.8 m/s defined as slow).

RESULTS

Prevalence rates were 17.7% for low ventilatory capacity, 14.7% for respiratory muscle weakness, 31.6% for dyspnea, 44.7% for moderate to severe mobility impairment and 43.6% for slow gait speed. Significant associations were found between low ventilatory capacity and slow gait speed (adjusted odds ratio (aOR) = 1.41, 95% confidence interval (CI) = 1.03-1.92), between respiratory muscle weakness and moderate to severe mobility impairment (aOR = 1.42, 95% CI = 1.03-1.95), and between dyspnea and high sedentary time (aOR = 1.98, 95% CI = 1.28-3.06) and slow gait speed (aOR = 1.70, 95% CI = 1.22-2.38).

CONCLUSION

Respiratory impairment and dyspnea are prevalent in sedentary older persons and are associated with objectively measured physical inactivity and poor performance-based mobility. Because they are modifiable, respiratory impairment and dyspnea should be considered in the evaluation of sedentary older persons.

Statin use and risk of COPD exacerbation requiring hospitalization

BACKGROUND

Despite recent studies that suggested statins' beneficial effects on chronic obstructive pulmonary disease (COPD) outcomes, the impact, if any, of statins on COPD exacerbations remains unclear. This study aimed to examine the association between statin use and risk of hospitalized COPD exacerbation, and to assess whether the association varied by statin initiation, dose, or duration of use.

METHODS

A retrospective nested case-control study among patients with COPD was conducted analyzing a nationwide health insurance claims database in Taiwan. Cases were subjects hospitalized for COPD exacerbations; each case was matched to 4 randomly selected controls on age, sex, cohort entry, and number of COPD-related outpatient visits by an incident-density sampling approach. Conditional logistic regressions were employed to quantify the COPD exacerbation risk associated with statin use.

RESULTS

The study cohort comprised 14,316 COPD patients, from which 1584 cases with COPD exacerbations and 5950 matched controls were identified. Any use of statins was associated with a 30% decreased risk of COPD exacerbation (95% confidence interval [CI], 0.56-0.88), and current use of statins was related to a greater reduced risk (adjusted odds ratio [OR] 0.60; 95% CI, 0.44-0.81). A dose-dependent reduced risk of COPD exacerbation by statins was observed (medium average daily dose: adjusted OR 0.60; 95% CI, 0.41-0.89; high daily dose: adjusted OR 0.33; 95% CI, 0.14-0.73). The reduced risk remained significant for either short or long duration of statin use.

CONCLUSIONS

Statin use was associated with a reduced risk of COPD exacerbation, with a further risk reduction for statins prescribed more recently or at high doses.

Respiratory impairment in older persons: when less means more

BACKGROUND

Among older persons, within the clinical context of respiratory symptoms and mobility, evidence suggests that improvements are warranted regarding the current approach for identifying respiratory impairment (ie, a reduction in pulmonary function).

METHODS

Among 3583 white participants aged 65 to 80 years (Cardiovascular Health Study), we calculated the prevalence of respiratory impairment using the current spirometric standard from the Global Initiative for Obstructive Lung Disease (GOLD) and an alternative spirometric approach termed "lambda-mu-sigma" (LMS). Results for GOLD- and LMS-defined respiratory impairment were evaluated for their (cross-sectional) association with respiratory symptoms and gait speed, and for the 5-year cumulative incidence probability of mobility disability.

RESULTS

The prevalence of respiratory impairment was 49.7% (1780/3583) when using the GOLD and 23.2% (831/3583) when using LMS. Differences in prevalence were most evident among participants who had no respiratory symptoms, with respiratory impairment classified more often by the GOLD (38.1% [326/855]) than LMS (12.3% [105/855]), as well as among participants who had normal gait speed, with respiratory impairment classified more often by the GOLD (46.4% [1003/2164]) than LMS (19.3% [417/2164]). Conversely, the 5-year cumulative incidence probability of mobility disability for respiratory impairment was higher for LMS than GOLD (0.313 and 0.249 for never-smokers, and 0.352 and 0.289 for ever-smokers, respectively), but was similar for normal spirometry by LMS or GOLD (0.193 and 0.185 for never-smokers, and 0.219 and 0.216 for ever-smokers, respectively).

CONCLUSIONS

Among older persons, the LMS approach (vs the GOLD approach) classifies respiratory impairment less frequently in those who are asymptomatic and is more strongly associated with mobility disability.

Effect of coexisting chronic obstructive pulmonary disease and cognitive impairment on health outcomes in older adults

OBJECTIVES

To determine the extent to which the co-occurrence of chronic obstructive pulmonary disease (COPD) and cognitive impairment affect adverse health outcomes in older adults.

DESIGN

Multicenter longitudinal cohort study.

SETTING

California, Pennsylvania, Maryland, and North Carolina.

PARTICIPANTS

Three thousand ninety-three community-dwelling adults aged 65 and older from the Cardiovascular Health Study. Four hundred thirty-one had chronic obstructive pulmonary disease (COPD) at study baseline.

MEASUREMENTS

Follow-up began at the second CHS visit and continued for 3 years. Spirometric criteria for airflow limitation served to establish COPD using the Lambda-Mu-Sigma method, which accounts for age-related changes in lung function. Cognitive impairment was evaluated using the modified Mini-Mental State Examination and claims data. Outcomes were respiratory-related and all-cause hospitalizations and death.

RESULTS

Participants with coexisting COPD and cognitive impairment had the highest rates of respiratory-related (adjusted hazard ratio (aHR) = 4.10, 95% confidence interval (CI) = 1.86-9.05) and all-cause hospitalizations (aHR = 1.34, 95% CI = 1.00-1.80) and death (aHR = 2.29, 95% CI = 1.18-4.45). In particular, individuals with both conditions had a 48% higher rate of all-cause hospitalizations (adjusted synergy index (aSI) = 1.48, 95% CI = 0.19-11.31) and a rate of death nearly three times as high (aSI = 2.74, 95% CI = 0.43-17.32) as the sum of risks for each respective outcome associated with having COPD or cognitive impairment alone. Nevertheless, tests for interaction were not statistically significant for the presence of synergism between the two conditions contributing to each of the outcomes. Therefore, it cannot be concluded that the combined effect of COPD and cognitive impairment is greater than additive.

CONCLUSION

Coexisting COPD and cognitive impairment have an additive effect on respiratory-related and all-cause hospitalizations and death. Optimizing outcomes in older adults with COPD and cognitive impairment will require that how to improve concurrent management of both conditions be determined.